Technical Field
The present disclosure relates to a distance measuring apparatus and a distance measuring method. More particularly, the present disclosure relates to a distance measuring apparatus and a distance measuring method for detecting a distance between driving vehicles.
Description of Related Art
The conventional distance measuring method is transmitting an ultrasound signal and receiving the ultrasound signal reflected from an object by an ultrasound transceiver device, so as to calculate a distance between the ultrasound transceiver device and the object. The distance can be obtained by multiplying the speed of sound by a time difference and dividing a multiplied value by 2, in which the time difference is between a time when the reflected ultrasound is received and a time when the ultrasound is transmitted. However, the smaller the reflected area of the object is, the worse accuracy of the distance measured by the conventional method becomes. Therefore, the conventional method is unable to effectively detect a distance between moving vehicles. Moreover, the farther the object is from the ultrasound transceiver device, the longer the time is for receiving the reflected ultrasound signal by the ultrasound transceiver device is, i.e., the worse the received signal. According to the result of an experiment, a distance detected by the conventional method is unable to exceed 10 meters. Therefore it is inadequate to detect a distance between moving vehicles.
Aiming at a moving vehicle, there is another method for detecting positions of other moving vehicles. In particular, each of moving vehicles uploads its position to a server by a global positioning system (GPS) and calculates a distance by the server according to each position of moving vehicles, However, it is unable to detect real-time positions of other moving vehicles by the GPS, which the efficiency is limited by data upload/download rates through communication networks. Accordingly, both of the aforementioned methods cannot provide accurate and immediate information of a distance between the moving vehicles for the drivers.